1. Field of the Invention
The present invention relates generally to a power supply circuit in an electronic device and a control method thereof, and more particularly, to a power supply circuit that includes a battery and receives power supplied from the outside in an electronic device, and a control method thereof
2. Description of the Related Art
The use of smart phones and tablet Personal Computers (PCs) has risen dramatically in recent years. The conventional smart phone or tablet PC has an internal battery that supplies power for operation. The smart phone or tablet PC includes a power interface such as a 30-pin connector, through which it receives externally supplied power. In this case, the conventional smart phone or tablet PC may interrupt the power supply from the battery to the system thereof
FIG. 1 is a block diagram of the conventional smart phone or tablet PC, which includes a 30-pin connector 1, a switch 2, and a battery 3.
The conventional smart phone or tablet PC receives the externally supplied power via the 30-pin connector 1, and delivers the received external power to the system thereof, at which time the power supply from the battery 3 to the system is interrupted. For example, the conventional smart phone or tablet PC may assign a JIG_ON signal to one pin of the 30-pin connector 1.
Upon receiving the JIG_ON signal, the switch 2 is controllable to be switched to the OFF state, in which case the battery 3 is disconnected from the system, interrupting the power supply from the battery 3 to the system.
Upon receiving the external power, the conventional smart phone or tablet PC interrupts all the connections between the battery 3 and the system. The conventional smart phone or tablet PC may undergo a process test before the battery is attached thereto. When there is a built-in battery, a JIG_ON signal may be assigned to a separate connector for the process test. In addition, the recent trend is that the 30-pin connector is replaced with a Universal Serial Bus (USB) connector.
Therefore, there is a need to develop a method of interrupting the power supply from the built-in battery for the USB connector to the system, and supplying the received external power to the system.